Heel Suspend Footbed With Pronation Adapting Mechanism

ABSTRACT

A thin footbed having incorporated spring structure that can adapt to a person&#39;s gait to avoid injuries and has minimal heel center pressure for prolonged comfort. The spring structure is made a carbon fiber and textile fabric hybrid material for high energy absorption capacity to prevent injuries from hard surface impacts.

CROSS-REFERENCE

Priority is claimed from the U.S. Provisional Patent Application No. 62/154,709, entitled “Flexible Carbon Fiber Composites and Method of Making Thereof” filed on Apr. 30, 2015, entirety of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present application relates to shoe sole, and more particularly to a footbed with pronation adapting mechanism that includes a pair of unique light-weight and durable carbon fiber springs attached to the footbed surface to adapt to foot pronation during gait cycles and to mediate body weight impacts to the foot and joints.

Note that the points discussed below may reflect the hindsight gained from the disclosed inventions, and are not necessarily admitted to be prior art.

The cyclic gaits of human biped running or walking include lateral heel rolling motions within healthy range of pronation or supination, such that when the heel initially strikes a surface, the ground impact forces are distributed and loaded on the outer edge of the heel. This foot heel gait increases stability and naturally protects the sensitive heel center from impact. Pronation is the motion that the foot rolls inward and supination is outwards (FIG. 1A). Excessive pronation and supination are common foot ailments that are the result of faulty foot mechanics and can lead to injuries in the foot, ankles, and knees. Pronation or spination can develop into permanent posture, overpronated foot tends to push off almost completely from the big toe and second toe, and the shock from the foot's impact doesn't spread evenly throughout the foot. Supinated foot, however, does not make enough “inward roll” in the foot's motion, the weight of the body isn't transferred at all to the big toe, forcing the outside of the foot and the smaller toes to take the majority of the overweight. Overpronation and underpronation (supination) are thus potentially harmful, and are associated with many overuse injuries.

Many alternative designs have been made in prior art footwear in an attempt to alleviate pronation problems and injuries that derive from the shortcomings in traditional shoe designs. These designs often require the mounting of mechanical lateral rocking devices made of rigid materials underneath the heel side and in the midsole of a shoe. However, these improvement designs neglect the impact of pressure on the foot heel center. Because the heel center contains major neuronal nerves that are sensitive and prone to irritation, even with cushioning, pressure on the heel center can create discomfort that leads to pain. With these shoes the center of the heel will press onto the rigid midsole during each walking step, causing discomfort and perhaps pain after wearing for an extended time. Surveys have shown a substantial number of US adults have experienced heel pain. FIG. 1B illustrates the locations of common areas of heel pain. The population with sensitive heels will not be able to feel comfortable with these types of shoes.

Some athletic shoes tend to have soft heel center cushioning, but because of the added thickness and width of the cushioning, there is an unwanted increase in the level of pronation/supination in initial landing that is much more than that of barefoot locomotion.

The shoe described in U.S. Pat. No. 5,678,327 is such an example. A rotatable device made of metal plates with a bow shape is constructed at the heel center of the shoe, although covered with a flat plate top, it can still cause discomfort to the heal center because of the rigidness of the metal. In U.S. Pat. No. 6,944,972, a hard upper and bottom plate separated by an element is incorporated to the shoe sole that can concentrate impact forces to the heel center. And in US 2013/0139412, a bulge structure made of composite material is configured around the heel center in the shoe sole, adding discomfort to the heel center.

What is needed in athletic footwear is a sole that can adapt to a person's gait to avoid injuries and has minimal heel center pressure for prolonged comfort. It is also desirable to have a high energy absorption capacity to prevent injuries from hard surface impacts.

SUMMARY

To overcome the shortcomings associated with present shoes and prior arts, we disclose an inventive footbed with a pronation adapting mechanism that has the following desirable characteristics.

In one embodiment, a footbed is configured to have a soft and suspended heel center that is free of rigid elements to alleviate discomfort and pain.

In one embodiment, a footbed is configured to have two attached heel side longitudinal springs that provide adequate support strength and can be adjustable separately to compensate pronation or supination abnormality.

In one embodiment, the two heel supporting springs of the example footbed are configured to deform independent of each other to provide lateral flexibility with rocking motion during each step, preventing excessive pronation induced injuries.

In one embodiment, a footbed is configured to be made of a hybrid material of thin layers of carbon fiber and texture fabrics and sufficiently thin and light weight to fit into in all types of shoes.

In one embodiment, a footbed is configured to contain a pair of thin arched springs made of a new class of hybrid elastic composite material with unprecedented material characteristics. The hybrid composite material is made by an inventive configuration in which thin layers of carbon fibers are laid uni-directionally along an arched frame, sandwiched between two or more layers of flexible textural fabric materials and cured in thermal plastic resin. While carbon fibers are brittle and inflexible in their conventional composite forms, this hybrid material has uniquely high elastic flexibility and durability, providing high spring constants in a lightweight and thin format

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed application will be described with reference to the accompanying drawings, which show important sample embodiments of the invention and which are incorporated in the specification hereof by reference, wherein:

FIG. 1A figuratively demonstrates a pronated, neutral and supinated ankle and foot.

FIG. 1B figuratively demonstrates the effects of shoes on heel center pain.

FIGS. 1C and 1D show a perspective view of an example footbed having a sole cushion configured with two independent carbon fiber composite side springs arched for gait adaption in accordance with this application. FIG. 1C figuratively shows the configuration of the footbed when the shoe heel is depressed; FIG. 1D figuratively shows the configuration of the footbed when the shoe heel is released.

FIG. 2A-2D figuratively illustrate example rear end section views of typical foot heel and footbed interactions during a gait cycle, adapting for pronation; FIG. 2A, shows a heel lifting state; FIG. 2B shows a heel vertical compression state; FIG. 2C shows an initial heel landing state for a typical pronated foot; FIG. 2D shows an initial heel landing state for a typical supinated foot.

FIG. 3 figuratively illustrates a perspective view of an expanded composition of a hybrid flexible carbon fiber composite material having a unidirectional carbon fiber layer sandwiched between two layers of traditional fabric materials.

FIG. 4A and FIG. 4B show a perspective view of an example carbon fiber composite spring structure designed for the foodbed in FIGS. 1C and 1D, having an arch shaped band-stripe configuration. FIG. 4A shows the arched spring in a released position; FIG. 4B shows the arched spring in a compressed state in accordance with this application.

DETAILED DESCRIPTION OF THE INVENTION

The numerous innovative teachings of the present application will be described with particular reference to presently preferred embodiments (by way of example, and not of limitation). The present application describes several embodiments, and none of the statements below should be taken as limiting the claims generally. For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and description and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale, some areas or elements may be expanded to help the understanding of embodiments of the invention.

The terms “first,” “second,” “third,” “fourth,” and the like in the description and the claims, if any, may be used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable. Furthermore, the terms “comprise,” “include,” “have,” and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, article, apparatus, or composition that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, apparatus, or composition. The term “longitudinal” as used throughout this detailed description and in the claims refers to a direction extending the length of a footbed. The term “lateral” refers to a direction extending the width of the footbed. The term “vertical” as used throughout this detailed description and in the claims refers to a direction generally perpendicular to a lateral and longitudinal direction. For example, in cases where a footbed is placed inside a shoe, the vertical direction may extend from the ground surface upward.

The term “footbed” refers to a non-movable or movable insole structure inside most shoe soles, used for cushioning or to provide a better fit or comfort for a foot. A footbed may be made of layers of leather, or polymer foam sheets. Conventional footbed's usefulness in absorbing body weight impact and providing support may be limited by the limited space of the shoe on its thickness. However, because it is such a critical part of the shoe in direct contact with the foot, a footbed has been considered and contemplated as an effective part of the shoe for correcting faulty foot mechanics.

The term “textile fabric” refers to any material made through weaving, knitting, spreading, crocheting, or bonding of threads or fiber strands that may be used in production of further goods. Cloth may be used synonymously with fabric in this application. The fabrics may include animal fabrics (skins), plant fabrics, mineral fabrics and synthetic fabrics.

Although various types of natural or synthetic polymeric materials and shapes have been applied in footbed constructions, extreme examples include placing rubber gels at the heel section or a bow shaped heel support, the improvement in comfort is unsatisfactory due to the insufficient elasticity of these materials. Theoretically, the impact energy absorption capacity of an elastic material is approximately proportional to the material's stiffness and its magnitude of deformation upon impact. For an ideal elastic material, similar to a spring, its energy absorption capability is a function of 0.5KX², where K is spring stiffness and X is displacement. This means that for a footbed to be effective in mediating body weight impact during walking or running its material's spring stiffness should be the harder the better. However, the harder in spring stiffness the lesser would it be in comfort feel to the foot, a long time dilemma in shoe industry.

This application provides a novel solution in design and in material to solve this dilemma.

The term “carbon fiber” or “carbon fibers” are used herein in the generic sense and are intended to include graphite fibers as well as amorphous carbon fibers. The carbon fiber is a material consisting of very thin filaments of carbon atoms. Carbon filament is generally first spun into filament yarns. The carbon fibers filament yarns may be further treated to improve handling qualities.

The term “carbon fiber composite” herein means the composite material generated when carbon fibers are bound together, usually with plastic polymer resin by heat, pressure or in a vacuum. Carbon fiber filament strands may be woven into a unidirectional, bidirectional mesh or screen like sheet. Carbon fiber strands may be interweaved with other material types of filaments and strands. The most commonly used resin is epoxy, but thermoplastic, polyurethane, vinyl ester, or polyester are also used. A carbon fiber composite can be directly shaped using a mold and placing the carbon fibers directly over the mold.

In reference to FIGS. 1C and 1D an example footbed 10 having a pair of adaptive springs for pronation and impact absorption is shown. Two sufficiently thin and resilient spring strips 12, 13 are sufficiently arched to provide energy absorption capacity. This is made possible by making a hybrid material with carbon fiber composite and traditional textile fabrics. Cover piece 11 upper side surface is for direct contacting the foot, can be made with traditional natural or synthetic polymeric materials for comfort and durability. Spring pieces 12 and 13 are mounted to the left and right underside of footbed cover piece 11 so that the heel center of footbed 10 is free from any additional hard attachment. The middle section of spring strips 12, 13 may be fixedly or removably glued or mechanically attached to the underside of the cover piece 11 so that cover piece 11 transfers impact pressure to spring strips 12 and 13 during gait cycles. Alternatively, the end sections of spring strips 12, 13 may be fixedly or removably glued or mechanically attached to a separate underside sheet or layer independent of cover piece 11, and such sheet together with cover piece 11 are then assembled into a footbed at the time of wearing by a user.

Preferably, cover piece 11 is made of leather or polymeric materials with foaming cushion, carved in shape of a normal foot, or a specifically designed shape to fit with a patient's foot. Spring strips 12 and 13 are attached to cover piece 11 on both the left and right sides around the heel section along the outer edge of the heel and longitudinally along the footbed. Alternatively, according to the need of a patient, either one or two springs may be attached or both springs are attached simultaneously at the cover piece 11.

Referring to FIGS. 2A to 2D, the rear sectional views of an example heel side of a foot illustrate that view footbed 10 configuration has at least two unique features: first, the heel center of a foot would be supported by the foam cover piece in combination with the two arched side springs that would deform adaptably and independently to distribute impacts along the edges; secondly, the heel center of a foot would be suspended with no direct support underneath. To illustrate, footbed 10 would have a typical 4 basic wearing states during a typical gait cycle: FIG. 2A shows the state when the heel 14 lifts upward; FIG. 2B shows the state when the heel 14 presses downward; FIG. 2C shows a pronated heel 14 pressing down; and FIG. 2D shows a supinated heel 14 pressing down.

When the foot moves upwards, heel 14 lists up, springs 12 and 13 would be in relaxed arched state, the ends separate from top cover piece 11, as shown in FIG. 2A. For normal pronation, upon foot moves down, heel 14 presses to the ground, springs 12 and 13 would be pressed flatter towards the ground, cover piece 11 would be in direct contact with heal 14 and in closer proximity to the ends of springs 12 and 13 as well, a person's weight would be fully distributed through a foot as shown in FIG. 2B. During this process the two side arch springs are compressed to near saturation and sufficiently flat, and the impact energy will be sufficiently converted and stored as spring potential energy. When the foot lifts, the springs will return to its preformed arched shape shown in FIG. 2A, releasing the stored energy by creating an upward thrust. Unlike polymer foams that convert most impact energy to heat during deformation, springs are efficient devices that return kinetic energy with little loss. Footbed 10 would provide much greater rebound forces than conventional footbeds and reduce heat generation.

In addition, footbed 10 can prevent or mitigate over-pronation and under-pronation. When a foot initially strikes a surface, the heel is usually in a supinated position, as shown in FIG. 2C, angling to the right side, the compressed spring 12 would thus provide an upward thrust that helps the foot correct to the neutral angle in FIG. 2B. Similarly for a pronated foot, the heel would strike the ground with an angle to the left side (FIG. 2D), the compressed spring 13 would thus provide an upward thrust to help the foot to the neutral position. Therefore, using the inventive footbed can prevent foot, ankle, and knee injuries caused by excessive pronation and re-supination in running and walking. A footbed design is preferred in this case, because for the close proximity of footbed to the foot a footbed would more effective in gait adapting than sole-based solutions, would therefore significantly reduce chances of overpronation common in typical shoes.

The inventive footbed simulates barefoot running experience. Wearing it the heel will be more naturally land on the ground to obtain stability, distributing and absorbing impact forces longitudinally along the outer edge of the heel and through the supporting arched springs of the footbed. At the same time, the heel will feel better and comforter due to the suspension formed at the heel center section of the footbed. The support provided by the springs at the two heel sides feels less irritable. For specific foot conditions and needs, footbed 10 can be easily tailored to compensate for a wearer's abnormal pronation by adjusting the two springs using different thicknesses, widths, or heights.

In summary, the disclosed footbed overcomes the shortcomings associated with present shoes on the market or in prior arts. First it adds a spring mechanism that is capable of vertical deformation which dampens harmful impact forces, and lateral rotational motion that adapts to heel pronation or spination. In addition, it has the capability to distribute impact forces to a larger surface area on the edges of the heel, increasing stability as well as comfort by eliminating pressure points. Second, the spring mechanism also has up-down vertical deformation function to damp the harmful ground impact shocks. Third, the heel center is suspended during compressing by the supporting springs, this provides improved cushioning which is especially beneficial for people suffering from pain in the central heel area such as plantar fasciitis patients. Fourth, with the use of hybrid carbon fiber material, the footbed is lightweight and thin such that it will not add stress during gait locomotion. This feature allows the inventive footbed potential to be adopted and utilized in all types of shoes. The spring supported footbed will provide strong rebound forces to recycle energy during walking, making walking or running less a burden, encouraging mobility for people of heavy weight.

The disclosed footbed design is enabled by being made of a novel carbon fiber material. The metal material that are used to make conventional springs lack the stiffness and the endurance necessarily required for constructing a thin and arched spring form useful for making part of a footbed. Increasing thickness of metal can increase spring stiffness but it also increases its weight. Carbon fiber composites have high strength to weight ratios, but all known pure carbon fiber composites are too brittle and are prone to fracture upon bending. Carbon fibers are generally held together by epoxy resin, though exceptional strong along the fiber direction, the binding strength between fibers is relatively weak due to the weak bonding strength of epoxy resin. Improvements are made by laying conventional carbon fiber composites crossing each other with various degrees and arrangements so that the resulting carbon fiber composites is strong in all directions, but this makes it also less flexible.

We disclose an inventive configuration and method to produce an elastically deformable hybrid carbon fiber composite (EDHC). As shown in FIG. 3, first carbon fiber layer 32 is generated by laying all of the carbon fibers uni-directionally so that maximum strength and flexibility are achieved along the fiber direction. To strengthen the inter-fiber binding and to increase the materials' strength against torsional force, two side layers 31 and 33 of textural fabrics are laid over carbon fiber layer 31, forming a hybrid multilayer sandwich-like material. This hybrid integration can be accomplished by sandwiching each unidirectional carbon fiber sheet 32 with fabric layers 31 and 33, and curing them together with an epoxy resin. The ratio of length to thickness is made sufficiently large so that an EDHC sheet is sufficiently flexible along the axis of the fiber strands.

Many types of textile fabrics can be used for EDHC material construction, the examples include cotton, rayon, linen, fiberglass cloth, Kevlar cloth, polymer cloth, and leather. Different fabrics result in differing force loads and bending characteristics. To make an arched spring with EDHC construction, the carbon fibers are laid over an arch mold so that the arch bending is along the carbon fiber strand direction. With carbon fiber's exceptional strength, the resulting EDHC spring can counter large loads while still be very thin. Comparing to pure carbon fiber composites the hybrid composite has shown orders of magnitude improvements in improved ability to deform elastically.

In reference to FIGS. 4A and 4B, an example EDHC arched spring for a footbed in FIGS. 1C and 1D is shown. In FIG. 4A arched spring 40 is arch shaped in a mold by laying epoxy resin soaked carbon fiber strands along the curvature where fiber strand ends lay along spring ends around end 42 and end 43. Layers of polymer cloth are placed over the carbon fiber layer as shown in FIG. 3, the layer sandwich is then subsequently cured at elevated temperatures over 60 degree. The curvature can vary based on particular needs on elasticity of a patient and/or the available space of a shoe. For example, the curvature may vary from 15 degree to 60 degree. A spring plate in FIG. 1A may comprise many mini EDHC arched springs paneled together or simply just one single entire piece molded from a mold. The carbon fiber springs preferably have a length (from one end to the other end of the curvature) to thickness ratio of bigger than 10 for flexibility and reliability. The preferred thickness ranges from 0.5-5 mm.

The spring 40 features at least one circular portion 44 connecting two peripheral feet portions 42 and 43 on both ends, which may or may not be bended according to a particular need or footbed design. Alternatively, feet portions 42 and 43 can bend towards each other to reduce the overall device length. In reference to FIG. 4B, spring 40 would absorbs the impact energy via compressing its arched curvature to a nearly flat position 45 upon application of a sufficiently large force. It absorbs the impact energy by building up internal tension inside the carbon fibers which would restore the arch shape when the force is removed. During spring compression, the center of the curvature 44 moves downwards vertically while the spring flattens out as the two feet 42 and 43 move laterally.

This arched sheet-band spring configuration also provides a compact profile which allows the springs be configured into tight spaces such as a footbed, shoe, or helmet applications. The center and edges of the spring are the preferred mounting points.

This class of elastically deformable lightweight material can also be used for other applications in addition to the disclosed footbed. Such a material may also be used in clothes and bags since they are lightweight, thin, and can maintain their original shape. Arched springs can be used in helmets, hip protectors, seats and beds.

The current invention is quite different to the spring-like devices described in prior art footwear using traditional materials. These spring-like devices are bulky and complex in design. They has the same shortcoming in heel centered construction as discussed in the previous sections that causes discomfort in extended use. These prior arts with spring mid-soles include US 2008/0052965, U.S. Pat. No. 5,343,639, U.S. Pat. No. 4,881,329, U.S. Pat. No. 4,342,158, US 2012/0285040, U.S. Pat. No. 5,212,878, U.S. Pat. No. 6,948,262, U.S. Pat. No. 6,282,814, U.S. Pat. No. 5,435,079, US 2011/0138652, U.S. Pat. No. 5,511,324, U.S. Pat. No. 8,347,526, U.S. Pat. No. 8,397,402, US 2011/0009982.

Numerous characteristics and advantages of the invention have been set forth in the foregoing description, together with details of the structure and function of the invention, and the novel features hereof are pointed out in the appended claims. The disclosure, however, is illustrative only, and changes may be made in detail, especially in matters, shape, size, and arrangement of parts, within the principle of the invention, to the full extend indicated by the broad general meaning of the terms in which the appended claims are expressed.

None of the description in the present application should be read as implying that any particular element, step, or function is an essential element which must be included in the claim scope: THE SCOPE OF PATENTED SUBJECT MATTER IS DEFINED ONLY BY THE ALLOWED CLAIMS. Moreover, none of these claims are intended to invoke paragraph six of 35 USC section 112 unless the exact words “means for” are followed by a participle. 

What is claimed:
 1. An athletic shoe for wearing on a foot of a user and for providing resilient cushioning while adapting to pronation in the gait cycle of the user during walking or running, comprising: a shoe upper portion that fits a dorsal surface contour of the foot of the user; a footbed configured for adapting to pronation that provides direct contact with a plantar surface of the foot of the user; and an outsole section that provides contact with a ground surface; wherein said shoe upper portion, said footbed section and said outsole section are mounted together for fitting about the foot of the user; and wherein said footbed comprises: an upper contact piece having textural polymer property for comfort feel of the plantar surface, said upper contact piece having a front portion and a heel portion that matches the user's foot shape, said heel portion having a left section, a center section and right section; and a first spring plate being arch-shaped longitudinally along the front portion and the heel portion of the footbed, said first spring plate having a center section, a front end and a rear end; wherein said first spring plate's center section is mounted underside of the left section of the heel portion of the upper contact piece, the front end and the rear end of the first spring plate being aligned longitudinally from the front portion to the heel portion of the upper contact piece; wherein said first spring plate comprises at least a layer of carbon fiber sheet and a layer of textile fabrics being molded together.
 2. The athletic shoe of claim 1, wherein said footbed configured for adapting to pronation that provides direct contact with a plantar surface of the foot of the user, further comprising: a second spring plate being arch-shaped longitudinally along the front portion and the heel portion of the upper contact piece, said second spring plate having a center section, a front end and a rear end; wherein said second spring plate's center section is mounted underside of the right section of the heel portion, the front end and the rear end of the second spring plate being aligned longitudinally from the front portion to the heel portion of the upper contact piece, and said second spring plate comprises at least a layer of carbon fiber sheet and a layer of textile fabrics being molded together.
 3. The athletic shoe of claim 1, wherein said carbon fiber sheet of the first spring plate comprises carbon fiber strands laying uni-directionally and longitudinally along the footbed.
 4. The athletic shoe of claim 2, wherein said carbon fiber sheet of the second spring plate comprises carbon fiber strands laying uni-directionally and longitudinally along the footbed.
 5. The athletic shoe of claim 1, wherein said textile fabrics of the first spring plate is selected from cotton cloth, rayon, silk, linen cloth, synthetic polymer cloth, fiber glass cloth, Kevlar cloth, and leather.
 6. The athletic shoe of claim 2, wherein said textile fabrics of the second spring plate is selected from cotton cloth, rayon, silk, linen cloth, synthetic polymer cloth, fiber glass cloth, Kevlar cloth, and leather.
 7. The athletic shoe of claim 1, wherein said first spring plate has a thickness ranging from 0.5-5 mm.
 8. The athletic shoe of claim 2, wherein said second spring plate has a thickness ranging from 0.5-5 mm.
 9. The athletic shoe of claim 1, wherein said first spring plate comprises another layer of textile fabrics, the carbon fiber sheet being molded between the two lays of textile fabrics.
 10. The athletic shoe of claim 2, wherein said second spring plate comprises another layer of textile fabrics, the carbon fiber sheet being molded between the two lays of textile fabrics.
 11. A footbed for use with an athletic shoe, configured for adapting to pronation that provides direct contact with a plantar surface of the foot of the user, comprising: an upper contact piece having textural polymer property for comfort feel of the plantar surface, said upper contact piece having a front portion and a heel portion that matches the user's foot shape, said heel portion having a left section, a center section and right section; and a first spring plate being arch-shaped longitudinally along the front portion and the heel portion of the footbed, said first spring plate having a center section, a front end and a rear end; wherein said first spring plate's center section is mounted underside of the left section of the heel portion of the upper contact piece, the front end and the rear end of the first spring plate being aligned longitudinally from the front portion to the heel portion of the upper contact piece; wherein said first spring plate comprises at least a layer of carbon fiber sheet and a layer of textile fabrics being molded together.
 12. The footbed of claim 11, wherein said footbed configured for adapting to pronation that provides direct contact with a plantar surface of the foot of the user, further comprising: a second spring plate being arch-shaped longitudinally along the front portion and the heel portion of the upper contact piece, said second spring plate having a center section, a front end and a rear end; wherein said second spring plate's center section is mounted underside of the right section of the heel portion, the front end and the rear end of the second spring plate being aligned longitudinally from the front portion to the heel portion of the upper contact piece, and said second spring plate comprises at least a layer of carbon fiber sheet and a layer of textile fabrics being molded together.
 13. The footbed of claim 11, wherein said carbon fiber sheet of the first spring plate comprises carbon fiber strands laying uni-directionally and longitudinally along the footbed.
 14. The footbed of claim 12, wherein said carbon fiber sheet of the second spring plate comprises carbon fiber strands laying uni-directionally and longitudinally along the footbed.
 15. The footbed of claim 11, wherein said textile fabrics of the first spring plate is selected from cotton cloth, rayon, silk, linen cloth, synthetic polymer cloth, fiber glass cloth, Kevlar cloth, and leather.
 16. The footbed of claim 12, wherein said textile fabrics of the second spring plate is selected from cotton cloth, rayon, silk, linen cloth, synthetic polymer cloth, fiber glass cloth, Kevlar cloth, and leather.
 17. The footbed of claim 11, wherein said first spring plate has a thickness ranging from 0.5-5 mm.
 18. The footbed of claim 12, wherein said second spring plate has a thickness ranging from 0.5-5 mm.
 19. The footbed of claim 11, wherein said first spring plate comprises another layer of textile fabrics, the carbon fiber sheet being molded between the two lays of textile fabrics.
 20. The footbed of claim 12, wherein said second spring plate comprises another layer of textile fabrics, the carbon fiber sheet being molded between the two lays of textile fabrics. 